Core barrel nose



Jan. 24, 1933. MACREADY CORE BARREL NOSE Filed March 14, 1929 g y/l I N VEN TOR.

Patented Jan. 24, 1933 GEORGE A. MACREADY, F LOS ANGELES, CALIFORNIA Conn BARREL nosn Application filed March 14, 1929. Serial No. 346,957.

My invention relates to improvements in earth or rock boring core drills of the double barrel type in which the function of the inner barrel is to advance downward without rotation over an underground core which has been cut by rotary cutters attached to a rotating outer barrel. My invention relates particularly to the lowermost fitting of the inner core barrel.

An object of my-invention is a core drill which can recover long lengths of core in soft friable material and retain the core in the core receiving barrel undetached and untwisted from the country rock while an observation is being made for the orientation of thecore to determine the direction of stratigraphic dip in the formation;

Another object of my invention is to pro-- vide a core barrel which will inscribe a series of longitudinal marks or graduations on the core as it is received in the core barrel for the purpose of identifying the direction of dip of strata penetrated.

Another object of my invention is to provide a simple core retaining device free from ointed projections liable to damage soft ormation cores. In accomplishing this I make use of a new principle, namely: the core is shaved clean of loose debris as it enters my nose, is prevented from expanding as it passes through my strong tightly fitting nose, but is allowed to expand above my nose to fit loosely in the core receiving barrel, this expansion forming a minute shoulder on the core which prevents it slipping backward.

With the foregoing and other objects in view which will be made manifest in the following detailed description and especially pointed out in the appended claims, reference is had to the accompanying drawing for illustrative embodiment of my invention, wherein:

Figure 1 is. a side elevation of the nose attached to the core receiving barrel;

Figure 2 is a longitudinal section through the nose and a portion of the core receiving barrel showing a core in partial section attached to the country rock;

Figure 3 is a longitudinal section through the nose; and

F igurot is a cross section nose taken at the line 4-4 in 'Similar numerals refer to throughout the several views.

In the accompanying drawing the core barrel nose is designated as 1 and is preferably an accurately machined tubular piece of steel having a bore 2. The nose,1 is attached tothe inner core receiving barrel 3 by means of rivets 4, although threads, other convenient means, or even a one-piece construction may be used.

The inner surface of the bore 2 is longitudinally fluted as at 5, thesevflutes extending from the lower edge 6 upward to the shoulder 9 at the lower end of the core receiving barrel 3. The depth, width, and number of these flutesmay be varied to suit the character of formation cored and diameter of core taken. For example I find that in one shale forma- 7 tion using a core receiving barrel of 2 inch standard 'pipe a good proportion is six grooves and six ribs of equal width with a. depth of one sixteenth inch so that the inside diameter is 1% inches at the grooves and 1% inches at the ribs. This proportion graduates the core with longitudinal marks at thirty degree intervals. The passage formed by bore 2 with flutes 5 is preferably of uniform size and shape between edge 6 so and shoulder 9.

The lower end of the nose 1 isbeveled or curved, as at 8, outwardly and upwardly the de ree of bevel varying to suit the formation. The annular edge 6 formed by the annular 185 bevel 8 meeting the wall of bore 2 is a cutting edge whose function is toshave the core to through the Figure 3. similar parts size and shape.

Above the upper ends of the flutings 5 the bore of the nose 1 is enlarged forming an annular ledge 7. The ledge 7 and the end of the core receiving barrel 3 are preferably machinedaccurately so that when pressure is applied to nosel from barrel 3 both parts will retain their alignment.

An essential feature of this invention is. that the internal diameter of the barrel 3 shall be slightly greater than the internal diameter of the nose 1 so that a shoulder 9 shall be-formed extending inwardly from the and is provide with suitable means for attaching the'nose to the core receiving barrel. The annular shoulder 12 on the external surface of the nose 1 forms a su port for'the nose and inner core receiving arrel so that they can rest on the outer cutting bit (not shown) without falling out when the core drill i hanging. Shoulder 12 can be dispensed with where metal thicknesses permit and otheigfmeans provided for support.

The operation of my invention is as follows. An outer rotary core cutting bit, not

shown in the drawings, is rotated by means of the outer barrel of the core drill to bore a hole having side walls 13 and bottom 14 leaving a central core 16. By means of a thrust bearing, not shown in the drawing, weight from the outer barrel. and drill pipe is applied to the inner core receiving barrel '3 and thence to nose 1 to force them downward as drilling progresses. An essential feature of the operation isthat the diameter of the core 16 must be greater than the diameter of the bore 2. The amount of the difference in diameters varies with the hardness of the formation. For example, I find that in shale format-ion using the dimensions mentioned previously with standard 2 inch pipe for core receiving) barrel a core 2 4 inches in diameter should e cut. For harder formation a smaller diameter core should be cut by undermining the nose.

As coring proceeds the nose 1 is forced down over t e core 16 so that the cutting edge 6 chips or shaves ofi a thin layer of the core 16 removing all shattered debris and cuttings usually clinging to a core with the result that the core 15 passing into the nose is absolutely clean,'completely fills the bore of the nose, and is given a cross section graduated by and corresponding to the flutes 5, which is one of the objects of my invention.

At the same time I find that the nose 1 either tends to stretch or the core attempts to ex and so that both fit tightly. The nose 1 is orced down over the core as fast as core is cut by the outer bit and the core emerges from the'top of the flutes into the slightly larger core receiving barrel 3. I find that at this point the core tends to expand slightly either because of release of pressure exerted by thestretched nose or because of a natural expansion due to removal from the country rock.

The expansion. ofthe core as it emerges from the nose 1 forms a minute shoulder 17 on great as to wash away the core or cause viration of the bit.

The invention disclosed in this application is an improvement over the lower portions of the inner core barrels described in my copending applications, Serial No. 107,980, which was filed May 10, 1926 and Serial No. 271,932, which was filed April 21, 1928.

It will be understood that various changes in detail of construction may be made without departing from the s irit or scope of the invention as defined by t e appended claims.

I claim as my invention:

must be carefully the core 15 which is of suflicient size to re- .to the surface as ra idly as necessary. Neither must the circu ation volume be so 1. A core barrel nose provided with an I annular chisel-like cuttin edge at the lower end thereof and a plurality of longitudinal grooves on the interior surface of said nose.

2. A core barrel nose provided with an annular chisel-like cuttin edge at the lower end thereof and a centra longitudinal passage extending upwardly from said edge, the interior surface of said passage having a plurality of longitudinal grooves and ribs of substantially equal circumferential width extending from said edge upwardly.

In testimony whereof I have :signed my name to this s ecification.

G ORGE A. MAGREADY. 

